bshell: re-organise build into three separate components

bshell: the front-end binary
bshell.runtime: contains the parser, compiler, and classes needed to run bshell scripts
bshell.core: contains the builtin commandlets and aliases

bshell.core/cmdlets/format-table.c

@@ -0,0 +1,8 @@
+#include <bshell/status.h>
+#include <fx/object.h>
+#include <fx/stream.h>
+
+enum bshell_status do_format_table(fx_object *object, fx_stream *dest)
+{
+	return BSHELL_SUCCESS;
+}